Cause of Disorder:
Her house was broken into and she was raped, she experienced a traumatic event. Thus being scared to be alone in her house and have the doors unlocked.

Disorder:
PTSD (Post-Traumatic Stress Disorder), OCD

Treatment:
Psychotherapy supplemented by dream therapy would be a possible treatment. Dream therapy involves recording the victim's nightmares and addressing the problems within in an attempt to rewrite the nightmare so as to make it less overpowering. Psychotherapy would be the basis of this treatment, and it involves the victim and a psychologist meeting and discussing the victim's fears in order to come to terms with them and get rid of the victim's obsessive behavior.